Aluminum alloy powders for powder bed fusion additive manufacturing processes

Abstract

A three-dimensional aluminum alloy part may be manufactured by a process in which a layer of aluminum alloy powder feed material is distributed over a substrate and scanned with a high-energy laser or electron beam in selective regions corresponding to a cross-section of the aluminum alloy part being formed. During the manufacturing process, the selective regions may melt and form a pool of molten aluminum alloy material. Thereafter, the pool of molten aluminum alloy material may cool and solidify into a solid layer of fused aluminum alloy material. During solidification of the pool of molten aluminum alloy material, solid phase particles may form within a solution of liquid phase aluminum prior to formation of solid phase aluminum dendrites. The resulting aluminum alloy part may exhibit a polycrystalline structure that predominantly includes a plurality of equiaxed grains, instead of columnar grains.

What is claimed is: 
     
         1 . An aluminum alloy powder for manufacturing a three-dimensional high-strength aluminum alloy part by a powder bed fusion additive manufacturing process, each particle of the aluminum alloy powder comprising:
 an aluminum alloy including, by weight, 13-25% silicon, 0.1-10% copper, and 0-2% magnesium,   wherein, when the aluminum alloy is heated to a first temperature greater than a liquidus temperature of the aluminum alloy and subsequently cooled to a second temperature less than the liquidus temperature of the aluminum alloy and greater than a solidus temperature of the aluminum alloy, the aluminum alloy transitions from a liquid phase to a multiphase system, and   wherein the multiphase system includes a solution of liquid phase aluminum and a solid phase of silicon particles dispersed throughout the liquid phase aluminum.   
     
     
         2 . The aluminum alloy powder of  claim 1  wherein the aluminum alloy comprises, by weight, 15-22% silicon, 2-5.1% copper, and 0.6-0.8% magnesium. 
     
     
         3 . The aluminum alloy powder of  claim 1  wherein the aluminum alloy comprises, by weight, 19-21% silicon, 3.5-4.1% copper, and aluminum as balance. 
     
     
         4 . The aluminum alloy powder of  claim 1  wherein the aluminum alloy comprises, by weight:
 greater than 0% iron and less than 9% iron, and 
 greater than 0% manganese and less than 5% manganese, and 
 wherein the multiphase system includes the solution of liquid phase aluminum, the solid phase of silicon particles, and another solid phase of iron-containing intermetallic particles dispersed throughout the liquid phase aluminum. 
 
     
     
         5 . An aluminum alloy powder for manufacturing a three-dimensional high thermal conductivity aluminum alloy part by a powder bed fusion additive manufacturing process, each particle of the aluminum alloy powder comprising:
 an aluminum alloy including, by weight:
 greater than 95% aluminum, and 
 greater than 0% and less than 5% of at least one nucleating agent, and 
   wherein the at least one nucleating agent comprises an element or compound having a solid solubility in aluminum of, by weight, less than 0.5% at temperatures less than 530 degrees Celsius,   wherein, when the aluminum alloy is heated to a first temperature greater than a liquidus temperature of the aluminum alloy and subsequently cooled to a second temperature less than the liquidus temperature of the aluminum alloy and greater than a solidus temperature of the aluminum alloy, the alloy transitions from a liquid phase to a multiphase system, and   wherein the multiphase system includes a solution of liquid phase aluminum and a solid phase of particles of the at least one nucleating agent dispersed throughout the liquid phase aluminum.   
     
     
         6 . The aluminum alloy powder of  claim 5  wherein the at least one nucleating agent comprises an element or compound having a solid solubility in aluminum of, by weight, less than or equal to 2.0% at the second temperature. 
     
     
         7 . A method of manufacturing a three-dimensional aluminum alloy part, the method comprising:
 (a) providing an aluminum alloy powder feed material;   (b) distributing a layer of the powder feed material over a substrate;   (c) scanning selective regions of the layer of the powder feed material with a high-energy laser or electron beam to form a pool of molten aluminum alloy material therein, the selective regions of the layer of the powder feed material corresponding to a cross-section of an aluminum alloy part being formed;   (d) terminating the laser or electron beam to cool and solidify the pool of molten aluminum alloy material into a solid layer of fused aluminum alloy material; and   (e) sequentially repeating steps (b) through (d) to form an aluminum alloy part made up of a plurality of solid layers of fused aluminum alloy material,   wherein, during solidification of the pool of molten aluminum alloy material, solid phase particles form within a solution of liquid phase aluminum prior to formation of solid phase aluminum dendrites, and   wherein, each of the solid layers of fused aluminum alloy material in the aluminum alloy part includes a continuous aluminum matrix phase that exhibits a polycrystalline structure and predominantly includes a plurality of equiaxed grains.   
     
     
         8 . The method of  claim 7  wherein, after termination of the laser or electron beam, the pool of molten aluminum alloy material is cooled at a rate in the range of 10 4  Kelvin per second to 10 6  Kelvin per second. 
     
     
         9 . The method of  claim 7  wherein, during solidification of the pool of molten aluminum alloy material, the molten aluminum alloy material transitions from an entirely liquid phase to a multiphase system in which the solid phase particles are dispersed throughout the solution of liquid phase aluminum. 
     
     
         10 . The method of  claim 7  wherein the solid phase particles serve as nuclei for the subsequent formation of the solid phase aluminum dendrites, and wherein, after the solid phase particles form within the solution of liquid phase aluminum, the solid phase aluminum dendrites nucleate and grow in multiple directions on the solid phase particles. 
     
     
         11 . The method of  claim 10  wherein growth of the solid phase aluminum dendrites is arrested when neighboring aluminum dendrites impinge upon one another and form grain boundaries. 
     
     
         12 . The method of  claim 7  wherein each particle of the aluminum alloy powder feed material comprises, by weight, 13-25% silicon, and wherein the solid phase particles comprise particles of silicon. 
     
     
         13 . The method of  claim 12  wherein each particle of the aluminum alloy powder feed material also comprises, by weight:
 greater than 0% iron and less than 9% iron, and 
 greater than 0% manganese and less than 5% manganese, and 
 wherein the solid phase particles comprise the particles of silicon and iron-containing intermetallic particles. 
 
     
     
         14 . The method of  claim 12  wherein each particle of the aluminum alloy powder feed material also comprises, by weight, 0.1-10% copper and 0-2% magnesium. 
     
     
         15 . The method of  claim 14  including:
 heating the aluminum alloy part at a temperature in the range of 180° C. to 210° C. for a duration of 0.5 hours to 7 hours to form at least one copper-containing precipitate phase within the aluminum matrix phase of each of the solid layers of fused aluminum alloy material in the aluminum alloy part. 
 
     
     
         16 . The method of  claim 7  wherein each particle of the aluminum alloy powder feed material comprises, by weight:
 greater than 95% aluminum, and 
 greater than 0% and less than 5% of at least one nucleating agent, and 
 wherein the at least one nucleating agent comprises an element or compound having a solid solubility in aluminum of, by weight, less than 0.5% at temperatures less than 530 degrees Celsius. 
 
     
     
         17 . The method of  claim 16  wherein each particle of the aluminum alloy powder feed material comprises, by weight, greater than 98% aluminum and less than 2% of the at least one nucleating agent. 
     
     
         18 . The method of  claim 16  wherein the at least one nucleating agent comprises at least one element or compound of titanium (Ti), boron (B), beryllium (Be), cobalt (Co), chromium (Cr), cesium (Cs), iron (Fe), hafnium (Hf), manganese (Mn), molybdenum (Mo), niobium (Nb), lead (Pb), sulfur (S), zirconium (Zr), antimony (Sb), scandium (Sc), selenium (Se), strontium (Sr), tantalum (Ta), vanadium (V), or tungsten (W). 
     
     
         19 . The method of  claim 18  wherein each particle of the aluminum alloy powder feed material comprises, by weight, at least one of greater than 0% B and less than 5% B, greater than or equal to 0.7% Be and less than 5% Be, greater than or equal to 0.9% Co and less than 5% Co, greater than or equal to 0.3% Cr and less than 5% Cr, greater than 0% Cs and less than 5% Cs, greater than or equal to 1.7% Fe and less than 5% Fe, greater than or equal to 0.4% Hf and less than 5% Hf, greater than or equal to 1.8% Mn and less than 5% Mn, greater than 0% Mo and less than 5% Mo, greater than 0% Nb and less than 5% Nb, greater than or equal to 1.4% Pb and less than 5% Pb, greater than 0% S and less than 5% S, greater than or equal to 0.9% Sb and less than 5% Sb, greater than or equal to 0.4% Sc and less than 5% Sc, greater than 0% Se and less than 5% Se, greater than or equal to 0.5% Sr and less than 5% Sr, greater than 0% Ta and less than 5% Ta, greater than or equal to 0.12% Ti and less than 5% Ti, greater than 0% V and less than 5% V, greater than 0% W and less than 5% W, or greater than 0% Zr and less than 5% Zr. 
     
     
         20 . The method of  claim 18  wherein each particle of the aluminum alloy powder feed material comprises, by weight, greater than 0.12% Ti, less than 5% Ti, and aluminum as balance.